1 /* ckgpav.f -- translated by f2c (version 19980913).
2 You must link the resulting object file with the libraries:
3 -lf2c -lm (in that order)
4 */
5
6 #include "f2c.h"
7
8 /* Table of constant values */
9
10 static integer c__2 = 2;
11 static integer c__6 = 6;
12 static integer c__9 = 9;
13
14 /* $Procedure CKGPAV ( C-kernel, get pointing and angular velocity ) */
ckgpav_(integer * inst,doublereal * sclkdp,doublereal * tol,char * ref,doublereal * cmat,doublereal * av,doublereal * clkout,logical * found,ftnlen ref_len)15 /* Subroutine */ int ckgpav_(integer *inst, doublereal *sclkdp, doublereal *
16 tol, char *ref, doublereal *cmat, doublereal *av, doublereal *clkout,
17 logical *found, ftnlen ref_len)
18 {
19 /* Initialized data */
20
21 static logical first = TRUE_;
22
23 extern /* Subroutine */ int vadd_(doublereal *, doublereal *, doublereal *
24 );
25 logical pfnd, sfnd;
26 integer sclk;
27 doublereal tmpv[3];
28 extern /* Subroutine */ int mtxv_(doublereal *, doublereal *, doublereal *
29 ), sct2e_(integer *, doublereal *, doublereal *), zznamfrm_(
30 integer *, char *, integer *, char *, integer *, ftnlen, ftnlen);
31 integer type1, type2;
32 extern /* Subroutine */ int zzctruin_(integer *);
33 doublereal omega[3];
34 char segid[40];
35 extern /* Subroutine */ int chkin_(char *, ftnlen);
36 doublereal descr[5];
37 extern /* Subroutine */ int dafus_(doublereal *, integer *, integer *,
38 doublereal *, integer *), ckbss_(integer *, doublereal *,
39 doublereal *, logical *), ckpfs_(integer *, doublereal *,
40 doublereal *, doublereal *, logical *, doublereal *, doublereal *,
41 doublereal *, logical *), moved_(doublereal *, integer *,
42 doublereal *), cksns_(integer *, doublereal *, char *, logical *,
43 ftnlen);
44 static char svref[32];
45 logical gotit;
46 doublereal xform[36] /* was [6][6] */;
47 extern /* Subroutine */ int xf2rav_(doublereal *, doublereal *,
48 doublereal *);
49 static integer svctr1[2];
50 extern logical failed_(void);
51 doublereal et;
52 integer handle;
53 logical needav;
54 extern /* Subroutine */ int ckmeta_(integer *, char *, integer *, ftnlen),
55 frmchg_(integer *, integer *, doublereal *, doublereal *);
56 integer refseg, center;
57 extern /* Subroutine */ int frinfo_(integer *, integer *, integer *,
58 integer *, logical *);
59 integer refreq, typeid;
60 extern /* Subroutine */ int chkout_(char *, ftnlen);
61 doublereal tmpmat[9] /* was [3][3] */;
62 static integer svrefr;
63 extern logical return_(void);
64 doublereal dcd[2];
65 integer icd[6];
66 extern /* Subroutine */ int mxm_(doublereal *, doublereal *, doublereal *)
67 ;
68 doublereal rot[9] /* was [3][3] */;
69
70 /* $ Abstract */
71
72 /* Get pointing (attitude) and angular velocity for a specified */
73 /* spacecraft clock time. */
74
75 /* $ Disclaimer */
76
77 /* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
78 /* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
79 /* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
80 /* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
81 /* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
82 /* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
83 /* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
84 /* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
85 /* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
86 /* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
87
88 /* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
89 /* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
90 /* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
91 /* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
92 /* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
93 /* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
94
95 /* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
96 /* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
97 /* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
98 /* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
99
100 /* $ Required_Reading */
101
102 /* CK */
103 /* SCLK */
104
105 /* $ Keywords */
106
107 /* POINTING */
108
109 /* $ Declarations */
110 /* $ Abstract */
111
112 /* The parameters below form an enumerated list of the recognized */
113 /* frame types. They are: INERTL, PCK, CK, TK, DYN. The meanings */
114 /* are outlined below. */
115
116 /* $ Disclaimer */
117
118 /* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
119 /* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
120 /* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
121 /* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
122 /* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
123 /* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
124 /* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
125 /* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
126 /* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
127 /* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
128
129 /* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
130 /* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
131 /* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
132 /* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
133 /* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
134 /* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
135
136 /* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
137 /* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
138 /* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
139 /* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
140
141 /* $ Parameters */
142
143 /* INERTL an inertial frame that is listed in the routine */
144 /* CHGIRF and that requires no external file to */
145 /* compute the transformation from or to any other */
146 /* inertial frame. */
147
148 /* PCK is a frame that is specified relative to some */
149 /* INERTL frame and that has an IAU model that */
150 /* may be retrieved from the PCK system via a call */
151 /* to the routine TISBOD. */
152
153 /* CK is a frame defined by a C-kernel. */
154
155 /* TK is a "text kernel" frame. These frames are offset */
156 /* from their associated "relative" frames by a */
157 /* constant rotation. */
158
159 /* DYN is a "dynamic" frame. These currently are */
160 /* parameterized, built-in frames where the full frame */
161 /* definition depends on parameters supplied via a */
162 /* frame kernel. */
163
164 /* ALL indicates any of the above classes. This parameter */
165 /* is used in APIs that fetch information about frames */
166 /* of a specified class. */
167
168
169 /* $ Author_and_Institution */
170
171 /* N.J. Bachman (JPL) */
172 /* W.L. Taber (JPL) */
173
174 /* $ Literature_References */
175
176 /* None. */
177
178 /* $ Version */
179
180 /* - SPICELIB Version 4.0.0, 08-MAY-2012 (NJB) */
181
182 /* The parameter ALL was added to support frame fetch APIs. */
183
184 /* - SPICELIB Version 3.0.0, 28-MAY-2004 (NJB) */
185
186 /* The parameter DYN was added to support the dynamic frame class. */
187
188 /* - SPICELIB Version 2.0.0, 12-DEC-1996 (WLT) */
189
190 /* Various unused frames types were removed and the */
191 /* frame time TK was added. */
192
193 /* - SPICELIB Version 1.0.0, 10-DEC-1995 (WLT) */
194
195 /* -& */
196
197 /* End of INCLUDE file frmtyp.inc */
198
199 /* $ Abstract */
200
201 /* This include file defines the dimension of the counter */
202 /* array used by various SPICE subsystems to uniquely identify */
203 /* changes in their states. */
204
205 /* $ Disclaimer */
206
207 /* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
208 /* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
209 /* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
210 /* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
211 /* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
212 /* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
213 /* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
214 /* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
215 /* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
216 /* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
217
218 /* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
219 /* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
220 /* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
221 /* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
222 /* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
223 /* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
224
225 /* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
226 /* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
227 /* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
228 /* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
229
230 /* $ Parameters */
231
232 /* CTRSIZ is the dimension of the counter array used by */
233 /* various SPICE subsystems to uniquely identify */
234 /* changes in their states. */
235
236 /* $ Author_and_Institution */
237
238 /* B.V. Semenov (JPL) */
239
240 /* $ Literature_References */
241
242 /* None. */
243
244 /* $ Version */
245
246 /* - SPICELIB Version 1.0.0, 29-JUL-2013 (BVS) */
247
248 /* -& */
249
250 /* End of include file. */
251
252 /* $ Brief_I/O */
253
254 /* Variable I/O Description */
255 /* -------- --- -------------------------------------------------- */
256 /* INST I NAIF ID of instrument, spacecraft, or structure. */
257 /* SCLKDP I Encoded spacecraft clock time. */
258 /* TOL I Time tolerance. */
259 /* REF I Reference frame. */
260 /* CMAT O C-matrix pointing data. */
261 /* AV O Angular velocity vector. */
262 /* CLKOUT O Output encoded spacecraft clock time. */
263 /* FOUND O True when requested pointing is available. */
264
265 /* $ Detailed_Input */
266
267 /* INST is the NAIF integer ID for the instrument, spacecraft, */
268 /* or other structure for which pointing and angular */
269 /* velocity are requested. For brevity we will refer to */
270 /* this object as the "instrument," and the frame fixed */
271 /* to this object as the "instrument frame" or */
272 /* "instrument-fixed" frame. */
273
274 /* SCLKDP is the encoded spacecraft clock time for which */
275 /* pointing and angular velocity are requested. */
276
277 /* The SPICELIB routines SCENCD and SCE2C respectively */
278 /* convert spacecraft clock strings and ephemeris time to */
279 /* encoded spacecraft clock. The inverse conversions are */
280 /* performed by SCDECD and SCT2E. */
281
282 /* TOL is a time tolerance in ticks, the units of encoded */
283 /* spacecraft clock time. */
284
285 /* The SPICELIB routine SCTIKS converts a spacecraft */
286 /* clock tolerance duration from its character string */
287 /* representation to ticks. SCFMT performs the inverse */
288 /* conversion. */
289
290 /* The C-matrix - angular velocity vector pair returned by */
291 /* CKGPAV is the one whose time tag is closest to SCLKDP */
292 /* and within TOL units of SCLKDP. (More in Particulars, */
293 /* below.) */
294
295 /* In general, because using a non-zero tolerance */
296 /* affects selection of the segment from which the */
297 /* data is obtained, users are strongly discouraged */
298 /* from using a non-zero tolerance when reading CKs */
299 /* with continuous data. Using a non-zero tolerance */
300 /* should be reserved exclusively to reading CKs with */
301 /* discrete data because in practice obtaining data */
302 /* from such CKs using a zero tolerance is often not */
303 /* possible due to time round off. */
304
305 /* REF is the desired reference frame for the returned */
306 /* pointing and angular velocity. The returned C-matrix */
307 /* CMAT gives the orientation of the instrument */
308 /* designated by INST relative to the frame designated by */
309 /* REF. When a vector specified relative to frame REF is */
310 /* left-multiplied by CMAT, the vector is rotated to the */
311 /* frame associated with INST. The returned angular */
312 /* velocity vector AV expresses the angular velocity of */
313 /* the instrument designated by INST relative to the */
314 /* frame designated by REF. See the discussion of CMAT */
315 /* and AV below for details. */
316
317 /* Consult the SPICE document "Frames" for a discussion */
318 /* of supported reference frames. */
319
320 /* $ Detailed_Output */
321
322 /* CMAT is a rotation matrix that transforms the components of */
323 /* a vector expressed in the reference frame specified by */
324 /* REF to components expressed in the frame tied to the */
325 /* instrument, spacecraft, or other structure at time */
326 /* CLKOUT (see below). */
327
328 /* Thus, if a vector v has components x,y,z in the REF */
329 /* reference frame, then v has components x',y',z' in the */
330 /* instrument fixed frame at time CLKOUT: */
331
332 /* [ x' ] [ ] [ x ] */
333 /* | y' | = | CMAT | | y | */
334 /* [ z' ] [ ] [ z ] */
335
336 /* If you know x', y', z', use the transpose of the */
337 /* C-matrix to determine x, y, z as follows: */
338
339 /* [ x ] [ ]T [ x' ] */
340 /* | y | = | CMAT | | y' | */
341 /* [ z ] [ ] [ z' ] */
342 /* (Transpose of CMAT) */
343
344 /* AV is the angular velocity vector. This is the axis about */
345 /* which the reference frame tied to the instrument is */
346 /* rotating in the right-handed sense at time CLKOUT. The */
347 /* magnitude of AV is the magnitude of the instantaneous */
348 /* velocity of the rotation, in radians per second. AV */
349 /* is expressed relative to the frame designated by REF. */
350
351 /* CLKOUT is the encoded spacecraft clock time associated with */
352 /* the returned C-matrix and the returned angular */
353 /* velocity vector. This value may differ from the */
354 /* requested time, but never by more than the input */
355 /* tolerance TOL. */
356
357 /* The particulars section below describes the search */
358 /* algorithm used by CKGPAV to satisfy a pointing */
359 /* request. This algorithm determines the pointing */
360 /* instance (and therefore the associated time value) */
361 /* that is returned. */
362
363 /* FOUND is true if a record was found to satisfy the pointing */
364 /* request. FOUND will be false otherwise. */
365
366 /* $ Parameters */
367
368 /* None. */
369
370 /* $ Exceptions */
371
372 /* 1) If a C-kernel file has not been loaded using FURNSH prior to */
373 /* a call to this routine, an error is signaled by a routine in */
374 /* the call tree of this routine. */
375
376 /* 2) If TOL is negative, found is set to .FALSE. */
377
378 /* 3) If REF is not a supported reference frame, an error is */
379 /* signaled by a routine in the call tree of this routine and */
380 /* FOUND is set to .FALSE. */
381
382 /* $ Files */
383
384 /* CKGPAV searches through files loaded by FURNSH to locate a */
385 /* segment that can satisfy the request for pointing and angular */
386 /* velocity for instrument INST at time SCLKDP. You must load a */
387 /* C-kernel file using FURNSH prior to calling this routine. */
388
389 /* $ Particulars */
390
391 /* How the tolerance argument is used */
392 /* ================================== */
393
394
395 /* Reading a type 1 CK segment (discrete pointing instances) */
396 /* --------------------------------------------------------- */
397
398 /* In the diagram below */
399
400 /* - "0" is used to represent discrete pointing instances */
401 /* (quaternions, angular velocity vectors, and associated */
402 /* time tags). */
403
404 /* - "( )" are used to represent the end points of the time */
405 /* interval covered by a segment in a CK file. */
406
407 /* - SCLKDP is the time at which you requested pointing. */
408 /* The location of SCLKDP relative to the time tags of the */
409 /* pointing instances is indicated by the "+" sign. */
410
411 /* - TOL is the time tolerance specified in the pointing */
412 /* request. The square brackets "[ ]" represent the */
413 /* endpoints of the time interval */
414
415 /* SCLKDP-TOL : SCLKDP+TOL */
416
417 /* - The quaternions occurring in the segment need not be */
418 /* evenly spaced in time. */
419
420
421 /* Case 1: pointing is available */
422 /* ------------------------------ */
423
424 /* SCLKDP */
425 /* \ TOL */
426 /* | / */
427 /* |/\ */
428 /* Your request [--+--] */
429 /* . . . */
430 /* Segment (0-----0--0--0--0--0--0---0--0------------0--0--0--0) */
431 /* ^ */
432 /* | */
433 /* CKGPAV returns this instance. */
434
435
436 /* Case 2: pointing is not available */
437 /* ---------------------------------- */
438
439 /* SCLKDP */
440 /* \ TOL */
441 /* | / */
442 /* |/\ */
443 /* Your request [--+--] */
444 /* . . . */
445 /* Segment (0-----0--0--0--0--0--0---0--0--0---------0--0--0--0) */
446
447
448 /* CKGPAV returns no pointing; the output */
449 /* FOUND flag is set to .FALSE. */
450
451
452
453 /* Reading a type 2, 3, 4, or 5 CK segment (continuous pointing) */
454 /* ------------------------------------------------------------- */
455
456 /* In the diagrams below */
457
458 /* - "==" is used to represent periods of continuous pointing. */
459
460 /* - "--" is used to represent gaps in the pointing coverage. */
461
462 /* - "( )" are used to represent the end points of the time */
463 /* interval covered by a segment in a CK file. */
464
465 /* - SCLKDP is the time at which you requested pointing. */
466 /* The location of SCLKDP relative to the time tags of the */
467 /* pointing instances is indicated by the "+" sign. */
468
469 /* - TOL is the time tolerance specified in the pointing */
470 /* request. The square brackets "[ ]" represent the */
471 /* endpoints of the time interval */
472
473 /* SCLKDP-TOL : SCLKDP+TOL */
474
475 /* - The quaternions occurring in the periods of continuous */
476 /* pointing need not be evenly spaced in time. */
477
478
479 /* Case 1: pointing is available at the request time */
480 /* -------------------------------------------------- */
481
482 /* SCLKDP */
483 /* \ TOL */
484 /* | / */
485 /* |/\ */
486 /* Your request [--+--] */
487 /* . . . */
488 /* . . . */
489 /* . . . */
490 /* Segment (==---===========---=======----------===--) */
491 /* ^ */
492 /* | */
493
494 /* The request time lies within an interval where */
495 /* continuous pointing is available. CKGPAV returns */
496 /* pointing at the requested epoch. */
497
498
499 /* Case 2: pointing is available "near" the request time */
500 /* ------------------------------------------------------ */
501
502 /* SCLKDP */
503 /* \ TOL */
504 /* | / */
505 /* |/\ */
506 /* Your request [--+--] */
507 /* . . . */
508 /* Segment (==---===========----=======---------===--) */
509 /* ^ */
510 /* | */
511
512 /* The request time lies in a gap: an interval where */
513 /* continuous pointing is *not* available. CKGPAV */
514 /* returns pointing for the epoch closest to the */
515 /* request time SCLKDP. */
516
517
518 /* Case 3: pointing is not available */
519 /* ---------------------------------- */
520
521 /* SCLKDP */
522 /* \ TOL */
523 /* | / */
524 /* |/\ */
525 /* Your request [--+--] */
526 /* . . . */
527 /* Segment (==---===========----=======---------===--) */
528
529 /* CKGPAV returns no pointing; the output */
530 /* FOUND flag is set to .FALSE. */
531
532
533
534 /* Tolerance and segment priority */
535 /* ============================== */
536
537 /* CKGPAV searches through loaded C-kernels to satisfy a pointing */
538 /* request. Last-loaded files are searched first. Individual files */
539 /* are searched in backwards order, so that between competing */
540 /* segments (segments containing data for the same object, for */
541 /* overlapping time ranges), the one closest to the end of the file */
542 /* has highest priority. CKGPAV considers only those segments that */
543 /* contain both pointing and angular velocity data, as indicated by */
544 /* the segment descriptor. */
545
546 /* The search ends when a segment is found that can provide pointing */
547 /* and angular velocity for the specified instrument at a time */
548 /* falling within the specified tolerance on either side of the */
549 /* request time. Within that segment, the instance closest to the */
550 /* input time is located and returned. */
551
552 /* The following four cases illustrate this search procedure. */
553 /* Segments A and B are in the same file, with segment A located */
554 /* further towards the end of the file than segment B. Both segments */
555 /* A and B contain discrete pointing data, indicated by the number */
556 /* 0. */
557
558
559 /* Case 1: Pointing is available in the first segment searched. */
560 /* Because segment A has the highest priority and can */
561 /* satisfy the request, segment B is not searched. */
562
563
564 /* SCLKDP */
565 /* \ TOL */
566 /* | / */
567 /* |/\ */
568 /* Your request [--+--] */
569 /* . . . */
570 /* Segment A (0-----------------0--------0--0-----0) */
571 /* ^ */
572 /* | */
573 /* | */
574 /* CKGPAV returns this instance */
575
576 /* Segment B (0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0) */
577
578
579
580 /* Case 2: Pointing is not available in the first segment searched. */
581 /* Because segment A cannot satisfy the request, segment B */
582 /* is searched. */
583
584
585 /* SCLKDP */
586 /* \ TOL */
587 /* | / */
588 /* |/\ */
589 /* Your request [--+--] */
590 /* . . . */
591 /* Segment A (0-----------------0--------0--0-----0) */
592 /* . . . */
593 /* Segment B (0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0) */
594 /* ^ */
595 /* | */
596 /* CKGPAV returns this instance */
597
598
599 /* Segments that contain continuous pointing data are searched in */
600 /* the same manner as segments containing discrete pointing data. */
601 /* For request times that fall within the bounds of continuous */
602 /* intervals, CKGPAV will return pointing at the request time. When */
603 /* the request time does not fall within an interval, then a time at */
604 /* an endpoint of an interval may be returned if it is the closest */
605 /* time in the segment to the user request time and is also within */
606 /* the tolerance. */
607
608 /* In the following examples, segment A is located further towards */
609 /* the end of the file than segment C. Segment A contains discrete */
610 /* pointing data and segment C contains continuous data, indicated */
611 /* by the "=" character. */
612
613
614 /* Case 3: Pointing is not available in the first segment searched. */
615 /* Because segment A cannot satisfy the request, segment C */
616 /* is searched. */
617
618 /* SCLKDP */
619 /* \ TOL */
620 /* | / */
621 /* |/\ */
622 /* Your request [--+--] */
623 /* . . . */
624 /* . . . */
625 /* Segment A (0-----------------0--------0--0-----0) */
626 /* . . . */
627 /* . . . */
628 /* Segment C (---=============-----====--------==--) */
629 /* ^ */
630 /* | */
631 /* | */
632 /* CKGPAV returns this instance */
633
634
635 /* In the next case, assume that the order of segments A and C in the */
636 /* file is reversed: A is now closer to the front, so data from */
637 /* segment C are considered first. */
638
639
640 /* Case 4: Pointing is available in the first segment searched. */
641 /* Because segment C has the highest priority and can */
642 /* satisfy the request, segment A is not searched. */
643
644 /* SCLKDP */
645 /* / */
646 /* | TOL */
647 /* | / */
648 /* |/\ */
649 /* Your request [--+--] */
650 /* . . . */
651 /* . . . */
652 /* Segment C (---=============-----====--------==--) */
653 /* ^ */
654 /* | */
655 /* CKGPAV returns this instance */
656
657 /* Segment A (0-----------------0--------0--0-----0) */
658 /* ^ */
659 /* | */
660 /* "Best" answer */
661
662
663 /* The next case illustrates an unfortunate side effect of using */
664 /* a non-zero tolerance when reading multi-segment CKs with */
665 /* continuous data. In all cases when the look-up interval */
666 /* formed using tolerance overlaps a segment boundary and */
667 /* the request time falls within the coverage of the lower */
668 /* priority segment, the data at the end of the higher priority */
669 /* segment will be picked instead of the data from the lower */
670 /* priority segment. */
671
672
673 /* Case 5: Pointing is available in the first segment searched. */
674 /* Because segment C has the highest priority and can */
675 /* satisfy the request, segment A is not searched. */
676
677 /* SCLKDP */
678 /* / */
679 /* | TOL */
680 /* | / */
681 /* |/\ */
682 /* Your request [--+--] */
683 /* . . . */
684 /* . . . */
685 /* Segment C (===============) */
686 /* ^ */
687 /* | */
688 /* CKGPAV returns this instance */
689
690 /* Segment A (=====================) */
691 /* ^ */
692 /* | */
693 /* "Best" answer */
694
695 /* $ Examples */
696
697
698 /* Suppose you have two C-kernel files containing data for the */
699 /* Voyager 2 narrow angle camera. One file contains predict values, */
700 /* and the other contains corrected pointing for a selected group */
701 /* of images, that is, for a subset of images from the first file. */
702
703 /* The following example program uses CKGPAV to get C-matrices and */
704 /* associated angular velocity vectors for a set of images whose */
705 /* SCLK counts (un-encoded character string versions) are contained */
706 /* in the array SCLKCH. */
707
708 /* If available, the program will get the corrected pointing values. */
709 /* Otherwise, predict values will be used. */
710
711 /* For each C-matrix, a unit pointing vector is constructed */
712 /* and printed along with the angular velocity vector. */
713
714 /* Note: if the C-kernels of interest do not contain angular */
715 /* velocity data, then the SPICELIB routine CKGP should be used to */
716 /* read the pointing data. An example program in the header of the */
717 /* SPICELIB routine CKGP demonstrates this. */
718
719
720
721 /* C */
722 /* C Constants for this program. */
723 /* C */
724 /* C -- The code for the Voyager 2 spacecraft clock is -32 */
725 /* C */
726 /* C -- The code for the narrow angle camera on the Voyager 2 */
727 /* C spacecraft is -32001. */
728 /* C */
729 /* C -- Spacecraft clock times for successive Voyager images */
730 /* C always differ by more than 0:0:400. This is an */
731 /* C acceptable tolerance, and must be converted to "ticks" */
732 /* C (units of encoded SCLK) for input to CKGPAV. */
733 /* C */
734 /* C -- The reference frame we want is FK4. */
735 /* C */
736 /* C -- The narrow angle camera boresight defines the third */
737 /* C axis of the instrument-fixed coordinate system. */
738 /* C Therefore, the vector ( 0, 0, 1 ) represents */
739 /* C the boresight direction in the camera-fixed frame. */
740 /* C */
741 /* IMPLICIT NONE */
742
743 /* INTEGER FILEN */
744 /* PARAMETER ( FILEN = 255 ) */
745
746 /* INTEGER NPICS */
747 /* PARAMETER ( NPICS = 2 ) */
748
749 /* INTEGER TIMLEN */
750 /* PARAMETER ( TIMLEN = 30 ) */
751
752 /* INTEGER REFLEN */
753 /* PARAMETER ( REFLEN = 32 ) */
754
755 /* CHARACTER*(TIMLEN) CLKCH */
756 /* CHARACTER*(FILEN) CKPRED */
757 /* CHARACTER*(FILEN) CKCORR */
758 /* CHARACTER*(REFLEN) REF */
759 /* CHARACTER*(FILEN) SCLK */
760 /* CHARACTER*(TIMLEN) SCLKCH ( NPICS ) */
761 /* CHARACTER*(TIMLEN) TOLVGR */
762
763 /* DOUBLE PRECISION AV ( 3 ) */
764 /* DOUBLE PRECISION CLKOUT */
765 /* DOUBLE PRECISION CMAT ( 3, 3 ) */
766 /* DOUBLE PRECISION SCLKDP */
767 /* DOUBLE PRECISION TOLTIK */
768 /* DOUBLE PRECISION VCFIX ( 3 ) */
769 /* DOUBLE PRECISION VINERT ( 3 ) */
770
771 /* INTEGER SC */
772 /* INTEGER I */
773 /* INTEGER INST */
774
775 /* LOGICAL FOUND */
776
777 /* CKPRED = 'voyager2_predict.bc' */
778 /* CKCORR = 'voyager2_corrected.bc' */
779 /* SCLK = 'voyager2_sclk.tsc' */
780 /* SC = -32 */
781 /* INST = -32001 */
782 /* SCLKCH(1) = '4/08966:30:768' */
783 /* SCLKCH(2) = '4/08970:58:768' */
784 /* TOLVGR = '0:0:400' */
785 /* REF = 'FK4' */
786 /* VCFIX( 1 ) = 0.D0 */
787 /* VCFIX( 2 ) = 0.D0 */
788 /* VCFIX( 3 ) = 1.D0 */
789
790 /* C */
791 /* C Loading the files in this order ensures that the */
792 /* C corrected file will get searched first. */
793 /* C */
794 /* CALL FURNSH ( CKPRED ) */
795 /* CALL FURNSH ( CKCORR ) */
796
797 /* C */
798 /* C Need to load a Voyager 2 SCLK kernel to convert from */
799 /* C clock strings to ticks. */
800 /* C */
801 /* CALL FURNSH ( SCLK ) */
802
803 /* C */
804 /* C Convert tolerance from VGR formatted character string */
805 /* C SCLK to ticks which are units of encoded SCLK. */
806 /* C */
807 /* CALL SCTIKS ( SC, TOLVGR, TOLTIK ) */
808
809
810 /* DO I = 1, NPICS */
811 /* C */
812 /* C CKGPAV requires encoded spacecraft clock. */
813 /* C */
814 /* CALL SCENCD ( SC, SCLKCH( I ), SCLKDP ) */
815
816 /* CALL CKGPAV ( INST, SCLKDP, TOLTIK, REF, CMAT, AV, */
817 /* . CLKOUT, FOUND ) */
818
819 /* IF ( FOUND ) THEN */
820
821 /* C */
822 /* C Use the transpose of the C-matrix to transform the */
823 /* C boresight vector from camera-fixed to reference */
824 /* C coordinates. */
825 /* C */
826 /* CALL MTXV ( CMAT, VCFIX, VINERT ) */
827 /* CALL SCDECD ( SC, CLKOUT, CLKCH ) */
828
829 /* WRITE (*,*) 'VGR 2 SCLK Time: ', CLKCH */
830 /* WRITE (*,*) 'VGR 2 NA ISS boresight ' */
831 /* . // 'pointing vector: ', VINERT */
832 /* WRITE (*,*) 'Angular velocity vector: ', AV */
833
834 /* ELSE */
835
836 /* WRITE (*,*) 'Pointing not found for time ', SCLKCH(I) */
837
838 /* END IF */
839
840 /* END DO */
841
842 /* END */
843
844
845 /* $ Restrictions */
846
847 /* Only loaded C-kernel segments containing both pointing and */
848 /* angular velocity data will be searched by this reader. Segments */
849 /* containing only pointing data will be skipped over. */
850
851 /* $ Literature_References */
852
853 /* None. */
854
855 /* $ Author_and_Institution */
856
857 /* C.H. Acton (JPL) */
858 /* N.J. Bachman (JPL) */
859 /* W.L. Taber (JPL) */
860 /* J.M. Lynch (JPL) */
861 /* B.V. Semenov (JPL) */
862 /* M.J. Spencer (JPL) */
863 /* R.E. Thurman (JPL) */
864 /* I.M. Underwood (JPL) */
865
866 /* $ Version */
867
868 /* - SPICELIB Version 5.3.0, 23-SEP-2013 (BVS) */
869
870 /* Updated to save the input frame name and POOL state counter */
871 /* and to do frame name-ID conversion only if the counter has */
872 /* changed. */
873
874 /* - SPICELIB Version 5.2.1, 03-JUN-2010 (BVS) */
875
876 /* Header update: description of the tolerance and Particulars */
877 /* section were expanded to address some problems arising from */
878 /* using a non-zero tolerance. */
879
880 /* - SPICELIB Version 5.2.0, 25-AUG-2005 (NJB) */
881
882 /* Updated to remove non-standard use of duplicate arguments */
883 /* in MTXV, MXM and VADD calls. */
884
885 /* - SPICELIB Version 5.1.2, 29-JAN-2004 (NJB) */
886
887 /* Header update: descriptions of input arguments REF and */
888 /* AV were expanded. */
889
890 /* - SPICELIB Version 5.1.1, 27-JUL-2003 (CHA) (NJB) */
891
892 /* Various header corrections were made. */
893
894 /* - SPICELIB Version 5.1.0, 23-FEB-1999 (WLT) */
895
896 /* The previous editions of this routine did not properly handle */
897 /* the case when TOL was negative. The routine now returns a */
898 /* value of .FALSE. for FOUND as is advertised above. */
899
900 /* - SPICELIB Version 5.0.0, 28-JUL-1997 (WLT) */
901
902 /* The previous routine incorrectly computed the angular */
903 /* velocity of the transformation from the request frame */
904 /* to the platform frame of the C-matrix for non-inertial */
905 /* reference frames. */
906
907 /* - SPICELIB Version 4.0.0, 19-SEP-1995 (WLT) */
908
909 /* The routine was upgraded so that the reference frame may */
910 /* be non-inertial. */
911
912 /* - SPICELIB Version 3.0.0, 5-OCT-1994 (WLT) */
913
914 /* The previous versions all computed an incorrect */
915 /* value for the angular velocity if the frame specified by */
916 /* REF was different from the reference frame of the segment */
917 /* from which the angular velocity was extracted. This has */
918 /* now been corrected. */
919
920 /* - SPICELIB Version 2.0.1, 10-MAR-1992 (WLT) */
921
922 /* Comment section for permuted index source lines was added */
923 /* following the header. */
924
925 /* - SPICELIB Version 2.0.0, 30-AUG-1991 (JML) */
926
927 /* 1) The Particulars section was updated to show how the */
928 /* search algorithm processes segments with continuous */
929 /* pointing data. */
930
931 /* 2) It was specified that the angular velocity vector */
932 /* gives the right-handed axis about which the instrument */
933 /* frame rotates. */
934
935 /* 3) The example program now loads an SCLK kernel. */
936
937 /* 4) FAILED is checked after the call to IRFROT to handle the */
938 /* case where the reference frame is invalid and the error */
939 /* handling is not set to abort. */
940
941 /* 5) FAILED is checked in the DO WHILE loop to handle the case */
942 /* where an error is detected by a SPICELIB routine inside the */
943 /* loop and the error handling is not set to abort. */
944
945 /* - SPICELIB Version 1.1.0, 02-NOV-1990 (JML) */
946
947 /* 1) The variable NEEDAV is no longer being saved. */
948 /* 2) In the example program, the calling sequences */
949 /* for SCENCD and CKGPAV were corrected. */
950 /* 3) The restriction that a C-kernel file must be loaded */
951 /* was explicitly stated. */
952
953 /* - SPICELIB Version 1.0.0, 07-SEP-1990 (RET) (IMU) */
954
955 /* -& */
956 /* $ Index_Entries */
957
958 /* get ck pointing and angular velocity */
959
960 /* -& */
961 /* $ Revisions */
962
963 /* - SPICELIB Version 5.2.0, 25-AUG-2005 (NJB) */
964
965 /* Updated to remove non-standard use of duplicate arguments */
966 /* in MTXV, MXM and VADD calls. */
967
968 /* - SPICELIB Version 4.1.0, 20-DEC-1995 (WLT) */
969
970 /* A call to FRINFO did not have enough arguments and */
971 /* went undetected until Howard Taylor of ACT. Many */
972 /* thanks go out to Howard for tracking down this error. */
973
974 /* - SPICELIB Version 4.0.0, 19-SEP-1995 (WLT) */
975
976 /* The routine was upgraded so that the reference frame may */
977 /* be non-inertial. */
978
979 /* - SPICELIB Version 3.0.0, 5-OCT-1994 (WLT) */
980
981 /* The previous versions all computed an incorrect */
982 /* value for the angular velocity if the frame specified by */
983 /* REF was different from the reference frame of the segment */
984 /* from which the angular velocity was extracted. This has */
985 /* now been corrected. */
986
987 /* Previously we were multiplying by the inverse of the */
988 /* rotation that transforms frames. */
989
990 /* - SPICELIB Version 2.0.0, 30-AUG-1991 (JML) */
991
992 /* 1) The Particulars section was updated to show how the */
993 /* search algorithm processes segments with continuous */
994 /* pointing data. */
995
996 /* 2) It was specified that the angular velocity vector */
997 /* gives the right-handed axis about which the instrument */
998 /* frame rotates. */
999
1000 /* 3) The example program now loads an SCLK kernel. */
1001
1002 /* 4) FAILED is checked after the call to IRFROT to handle the */
1003 /* case where the reference frame is invalid and the error */
1004 /* handling is not set to abort. */
1005
1006 /* 5) FAILED is checked in the DO WHILE loop to handle the case */
1007 /* where an error is detected by a SPICELIB routine inside the */
1008 /* loop and the error handling is not set to abort. */
1009
1010 /* - SPICELIB Version 1.1.0, 02-NOV-1990 (JML) */
1011
1012 /* 1) The variable NEEDAV is no longer being saved. */
1013 /* 2) In the example program, the calling sequences */
1014 /* for SCENCD and CKGPAV were corrected. */
1015 /* 3) The restriction that a C-kernel file must be loaded */
1016 /* was explicitly stated. */
1017
1018 /* - Beta Version 1.1.0, 30-AUG-1990 (MJS) */
1019
1020 /* The following changes were made as a result of the */
1021 /* NAIF CK Code and Documentation Review: */
1022
1023 /* 1) The variable SCLK was changed to SCLKDP. */
1024 /* 2) The variable INSTR was changed to INST. */
1025 /* 3) The variable IDENT was changed to SEGID. */
1026 /* 4) The declarations for the parameters NDC, NIC, NC, and */
1027 /* IDLEN were moved from the "Declarations" section of the */
1028 /* header to the "Local parameters" section of the code below */
1029 /* the header. These parameters are not meant to modified by */
1030 /* users. */
1031 /* 5) The header was updated to reflect the changes. */
1032
1033 /* - Beta Version 1.0.0, 04-JUN-1990 (RET) (IMU) */
1034
1035 /* -& */
1036
1037 /* SPICELIB functions */
1038
1039
1040 /* Local parameters */
1041
1042 /* NDC is the number of double precision components in an */
1043 /* unpacked C-kernel segment descriptor. */
1044
1045 /* NIC is the number of integer components in an unpacked */
1046 /* C-kernel segment descriptor. */
1047
1048 /* NC is the number of components in a packed C-kernel */
1049 /* descriptor. All DAF summaries have this formulaic */
1050 /* relationship between the number of its integer and */
1051 /* double precision components and the number of packed */
1052 /* components. */
1053
1054 /* IDLEN is the length of the C-kernel segment identifier. */
1055 /* All DAF names have this formulaic relationship */
1056 /* between the number of summary components and */
1057 /* the length of the name (You will notice that */
1058 /* a name and a summary have the same length in bytes.) */
1059
1060
1061 /* Saved frame name length. */
1062
1063
1064 /* Local variables */
1065
1066
1067 /* Saved frame name/ID item declarations. */
1068
1069
1070 /* Saved frame name/ID items. */
1071
1072
1073 /* Initial values. */
1074
1075
1076 /* Standard SPICE error handling. */
1077
1078 if (return_()) {
1079 return 0;
1080 } else {
1081 chkin_("CKGPAV", (ftnlen)6);
1082 }
1083
1084 /* Initialization. */
1085
1086 if (first) {
1087
1088 /* Initialize counter. */
1089
1090 zzctruin_(svctr1);
1091 first = FALSE_;
1092 }
1093
1094 /* Need angular velocity data. */
1095 /* Assume the segment won't be found until it really is. */
1096
1097 needav = TRUE_;
1098 *found = FALSE_;
1099
1100 /* If the tolerance is less than zero, we go no further. */
1101
1102 if (*tol < 0.) {
1103 chkout_("CKGPAV", (ftnlen)6);
1104 return 0;
1105 }
1106
1107 /* Begin a search for this instrument and time, and get the first */
1108 /* applicable segment. */
1109
1110 ckbss_(inst, sclkdp, tol, &needav);
1111 cksns_(&handle, descr, segid, &sfnd, (ftnlen)40);
1112
1113 /* Keep trying candidate segments until a segment can produce a */
1114 /* pointing instance within the specified time tolerance of the */
1115 /* input time. */
1116
1117 /* Check FAILED to prevent an infinite loop if an error is detected */
1118 /* by a SPICELIB routine and the error handling is not set to abort. */
1119
1120 while(sfnd && ! failed_()) {
1121 ckpfs_(&handle, descr, sclkdp, tol, &needav, cmat, av, clkout, &pfnd);
1122 if (pfnd) {
1123
1124 /* Found one. If the data aren't already referenced to the */
1125 /* requested frame, rotate them. */
1126
1127 dafus_(descr, &c__2, &c__6, dcd, icd);
1128 refseg = icd[1];
1129
1130 /* Look up the id code for the requested reference frame. */
1131
1132 zznamfrm_(svctr1, svref, &svrefr, ref, &refreq, (ftnlen)32,
1133 ref_len);
1134 if (refreq != refseg) {
1135
1136 /* We may need to convert the output ticks CLKOUT to ET */
1137 /* so that we can get the needed state transformation */
1138 /* matrix. This is the case if either of the frames */
1139 /* is non-inertial. */
1140
1141 frinfo_(&refreq, ¢er, &type1, &typeid, &gotit);
1142 frinfo_(&refseg, ¢er, &type2, &typeid, &gotit);
1143 if (type1 == 1 && type2 == 1) {
1144
1145 /* Any old value of ET will do in this case. We'll */
1146 /* use zero. */
1147
1148 et = 0.;
1149 } else {
1150
1151 /* Look up the spacecraft clock id to use to convert */
1152 /* the output CLKOUT to ET. */
1153
1154 ckmeta_(inst, "SCLK", &sclk, (ftnlen)4);
1155 sct2e_(&sclk, clkout, &et);
1156 }
1157
1158 /* Get the transformation from the requested frame to */
1159 /* the segment frame at ET. */
1160
1161 frmchg_(&refreq, &refseg, &et, xform);
1162
1163 /* If FRMCHG detects that the reference frame is invalid */
1164 /* then return from this routine with FOUND equal to false. */
1165
1166 if (failed_()) {
1167 chkout_("CKGPAV", (ftnlen)6);
1168 return 0;
1169 }
1170
1171 /* First transform the attitude information. Get the */
1172 /* rotation and angular velocity associated with the */
1173 /* transformation from request frame to segment frame. */
1174 /* Then convert CMAT so that it maps from request frame */
1175 /* to C-matrix frame. */
1176
1177 xf2rav_(xform, rot, omega);
1178 mxm_(cmat, rot, tmpmat);
1179 moved_(tmpmat, &c__9, cmat);
1180
1181 /* Now transform the angular velocity information. */
1182 /* Currently we have OMEGA (the angular velocity of */
1183 /* the transformation from REF frame to the base */
1184 /* frame of the C-matrix), and AV the angular velocity */
1185 /* of the transformation from the C-MATRIX reference */
1186 /* system to the platform of the C-matrix. */
1187
1188 /* The angular velocity of the C-MATRIX relative to */
1189 /* requested frame is given by */
1190
1191 /* T */
1192 /* OMEGA + ROT * AV */
1193
1194 /* Here's why. */
1195
1196 /* The transformation from the request frame to the frame */
1197 /* of the C-kernel looks like this: */
1198
1199 /* [ ] */
1200 /* [ ROT : 0 ] */
1201 /* [................ ] */
1202 /* [ dROT : ] */
1203 /* [ ---- : ROT ] */
1204 /* [ dt : ] */
1205
1206 /* The transformation from the C-kernel reference frame to */
1207 /* the C-kernel platform frame looks like: */
1208
1209
1210 /* [ ] */
1211 /* [ CMAT : 0 ] */
1212 /* [ ............... ] */
1213 /* [ dCMAT : ] */
1214 /* [ ---- : CMAT ] */
1215 /* [ dt : ] */
1216
1217
1218 /* The transformation from the request frame to the platform */
1219 /* frame is the product shown below */
1220
1221
1222 /* [ ][ ] */
1223 /* [ CMAT : 0 ][ ROT : 0 ] */
1224 /* [ ............... ][................ ] */
1225 /* [ dCMAT : ][ dROT : ] */
1226 /* [ ---- : CMAT ][ ---- : ROT ] */
1227 /* [ dt : ][ dt : ] */
1228
1229
1230 /* [ : ] */
1231 /* [ CMAT * ROT : 0 ] */
1232 /* = [ ........................................ ] */
1233 /* [ dCMAT dROT : ] */
1234 /* [ ---- * ROT + CMAT * ---- : CMAT * ROT ] */
1235 /* [ dt dt : ] */
1236
1237
1238 /* In general, the angular velocity matrix of a */
1239 /* transformation R is given by */
1240
1241 /* T */
1242 /* dR */
1243 /* -- * R */
1244 /* dt */
1245
1246 /* Substituting the appropriate components of the matrix */
1247 /* in for R we have: */
1248
1249 /* T T */
1250 /* OMEGA = ROT * dCMAT * CMAT * ROT */
1251 /* CMAT*ROT ----- */
1252 /* dt */
1253
1254 /* T */
1255 /* dROT T */
1256 /* + ---- * CMAT * CMAT * ROT */
1257 /* dt */
1258
1259
1260 /* T */
1261 /* = ROT * OMEGA * ROT + OMEGA */
1262 /* CMAT ROT */
1263
1264
1265 /* Consider the first term of the final expression. If we */
1266 /* let "x" stand for the cross product operation, then by */
1267 /* definition for any vector V: */
1268
1269
1270 /* T */
1271 /* ROT * OMEGA * ROT * V */
1272 /* CMAT */
1273
1274
1275 /* T */
1276 /* = ROT * (AV x ROT*V ) */
1277 /* CMAT */
1278
1279 /* (since rotations distribute across cross */
1280 /* products) */
1281
1282 /* T T */
1283 /* = (ROT * AV ) x ( ROT * ROT*V ) */
1284 /* CMAT */
1285
1286
1287 /* T */
1288 /* = (ROT * AV ) x V */
1289 /* CMAT */
1290
1291 /* Thus OMEGA is the matrix form of the cross */
1292 /* CMAT*ROT */
1293
1294 /* T */
1295 /* product operation {( ROT *AV ) + AV } x . */
1296 /* CMAT ROT */
1297
1298
1299 mtxv_(rot, av, tmpv);
1300 vadd_(omega, tmpv, av);
1301 }
1302 *found = TRUE_;
1303 chkout_("CKGPAV", (ftnlen)6);
1304 return 0;
1305 }
1306 cksns_(&handle, descr, segid, &sfnd, (ftnlen)40);
1307 }
1308 chkout_("CKGPAV", (ftnlen)6);
1309 return 0;
1310 } /* ckgpav_ */
1311
1312